Ionizing radiation can cause total failure resulting from total dose (long accumulation of radiation) in semiconductor ICs. In high radiation environments, such as space applications, ionizing radiation creates trapped charge and interface states in dielectric layers. That is, due to prolonged radiation exposure (total dose) a charge can build up at an interface between an oxide and SOI devices. This build up will eventually change the charge flow at the SOI interface. For example, trapped charge in the buried oxide (BOX) leads to increased backgate leakage and trapped charge in the STI increases leakage through the sidewall device. If the backgate or sidewall threshold voltage is allowed to move far enough from the design point, the circuitry can fail to operate.
Methods to prevent total dose effects include hardening the STI or BOX individually, which only addresses one possible means of failure. Consequently, there is a need to improve protection schemes from radiation events in ICs.
Accordingly, there exists a need in the art to overcome the deficiencies and limitations described hereinabove.